Process for treating hydrocarbon oils



June 25, 1929.

C. J. GREENSTREET PROCESS FOR TREATING HYDROCARBON OILS Ori ginal Filed Aug. 9, 1920 5 Sheets-She'et l Av-amm,

June 25, 1929. c. J. GREENSTREET PROCESS FOR TREATING HYDROCARBON OILS Original Filed Aug. 1920 5 Sheets-Sheet 2 June 25, 1929. Q J GREENSTREET 1,718,913

PROCESS FOR TREATING HYDROGARBON OILS Original Filed Aug. 9, 1920 5 Sheets-Sheet 5 atented June 25,

UNITED emirates Jason ennnus'rsunr, or new YORK, N. Y., ASSIGNOR T0 GASOLINE cos:

PORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

;'.PROCESS FOR TREATING HYDROCARBON OI LS.

Application filed August 9, 1920. Serial No. 402,381.

llhis invention relates to a process for treating hydrocarbon oils, and more particularly to a process in which heavy hydro carbons are decomposed or cracked by heat and pressure to lighter hydrocarbons.

In cracking heavy hydrocarbons by the application of heat and pressure to, produce lighter hydrocarbons suitable for use as a motor fluid, the yield and. quantity of the product obtained governed to a very great extent by the temperatures and pressures employed and the time and nianner of heating the oil. For instance, if the oils are subjected to an excessively high temperature above that necessary to crack the oil, there is a tendency for the oil to decompose largely to carbon and uncondensable gases, and also for the volatile liquid hydrocarbons formed in the treatment to be further decomposed to carbon and gases, especially if the heating is continued for too long a period of time. Accordingly, if the heat treatment of the oil is not uniform and the oil is locally overheated, or, if portions of the oil stick to, or remain too long in contact with, the heating means, the yield of motor fluid is decreased through the excessive formation of gas and carbon at the overheated 1 laces. Moreover, portions of the oil may at at at as e scorched or burned producing 1mpurlti es 1n the product which require the use of excessive amounts of purifying chemicals,

or which may injure the product so that it cannot be thoroughly purified.

One object of the present invention is to provide a process in which the hydrocarbons to be treated are subjected to a uniform and accurately controlled heat treatment for a definite period of time.

A further' object of the invention is to provide a process in which the manner and length of time of treatment of the oil may be accurately controlled.

A further object of the invention is to provide a process in which the formation of scorched and resinous substances and other impurities in the lighter hydrocarbon products obtained in the process is avoided.

With these and other objects in view, the invention consists in the process described in the following specification and defined in the claims.

The various features of the invention are illustrated in the accompanying drawings in which:

Fig. 1 is a vertical section, taken on line 11 of Fig. 2, of an oil cracking furnace and control house embodying the preferred form of an apparatus for carrying on the process;

Fig. 2 is an elevation partly in section on line 22 of Fig. 1, and partly in a section through the control house of the oil cracking apparatus, and

Fig. 3.is a plan view partly in section on line 33 of Fig. 1.

In the present invention the hydrocarbon oil to be treated is supplied at a regulated rate to a number of uniformly heated cracking coils. Before entering the coils, the oil is mixed with steam and passes with the steam into the heated portion of the coils. The oil is rapidly vaporized upon entering the coils and. the mixture of steam and oil vapors is heated to a. temperature at which the cracking reaction takes place. Throughout its further passage through the heated coils, the steam and oil mixture is maintained uniformly at this cracking temperature until a substantial portion of the oil is .cracked to form a product containing volatile hydrocarbon liquids suitable for use as a motor fluid. A uniform cracking temperature throughout the length of the coils is obtained by maintaining a furnace for heating the cracking coils at a substantially uniform temperature somewhat higher than that to which oil undergoing treatment is to be treated and passing the oil through the coils at a substantially uniform rate. The steam and cracked vapors leaving the coils are immediately chilled, by direct contact with jets of Water, or other suitable fluid, to a temperature atfwhich the cracking reaction ceases, and the chilled vapors are thereafter condensed in a suitable condenser.

Referring more specifically to the accompanying drawing, oil to be treated is supplied through an oil supply pipe 10 to a pump 12, and is forced by the pump through. a delivery pipe 14, to a distributing header 16. From the distribution header 16, the

oil is distributed to a number of pipes 18,

corresponding in number to the coils inof the pipes 18, are measured by means of pressure gauges 19 and oil meters 20, and the rate of supply of the oil is regulated and kept constant by means of valves 22, in the pipes 18.- The oil passes from the meters 20, through pipes 24, to mixing nozzles 26, in which it is mixed with steam before entering the cracking coils. Steam for mixing with the oil in the mixing nozzles 26 is supplied from a steam-header 30 through a number of supply pipes 32. The rate of supply of steam is controlled by means of alves 34 in the pipes 32, and the pressure is measured by means of a pressure gauge 36. Satisfactory results are obtained when the pressure in the steam header is approximately 125 pounds per square inch, and the pressure of the oil approximately 110 pounds per square inch. The quantity of steam sup plied should, under these conditions, be approximately fit'teen per cent of the quantity of oil supplied.

From the mixing nozzles 26, the mixture of steam and oil passes through connecting pipes 38 to the inlet ends of a number of heating or cracking coils -10 of seamless steel tubing suspended in a furnace 42. lVrought iron tubing may be used in place of steel tubing but in this case the seams of the tubing should be welded together electrically, or fused together by means of a thermite mixture or blow pipe or other means by which a substantially uniform,

homogeneous structure is obtained throughout all portions of the wall of the tube. A properly constructed wrought iron tube of this typemay be used without danger of the seams of the tube opening and appears to have the advantage that the wrought iron tends to increase the quantity of oil which may be cracked in a coil of a given length. Upon entering the furnace the oil is vaporized and the steam and oil vapors are raised to a temperature at which the heavy hydrocarbons of the oil break down or crack to form a substantial portion of light or easily volatile hydrocarbons similar to gasolene and suitable for use as a motor The speed of travel of the oil and steam is so proportioned to the length of the coil that sufiicient time will be given for the desired conversion of the heavy hydrocarbons. It is very desirable to have the oil pass through the coils at a very high rate of speed since this, together with the steam, serves to prevent any carbon or tarry matters from settling out of the flowing fluids and from sticking to the sides of the heating coil. Very good results are obtained in cracking gas oil, for instance,

when a pipe of two inches in diameter and four hundred feed in length is employed, and when the oil is supplied at the rate of three and one half gallons per coil per minute.

The temperature of the vapors in the coils is adjusted when treating different types of oil, a higher temperature being used in cracking kerosene and other comparatively light distillates than is used in cracking gas oil or'light fuel oil. In cracking a gas oil, for instance, the temperature of the oil is ordinarily maintained slightly below 1100 F.

After the oil has been heated and maintained at the proper cracking temperature for a length of time suflicient to form the desired products, it is immediately removed from the coil and chilled to check the further rapid cracking of the hydrocarbons. For this purpose the steam and oil vapors from the coils 40 pass through short connecting pipes -14 into cooling drums 45, one drum being provided for each coil. \Vater or other suitable cooling liquid is injected into the drums through supply pipes 46, and comes into direct contact with the hot cracked vapors. The water is thereupon rapidly vaporized, absorbing a large amount of heat from the cracked vapors, and chills the vapors to a temperature at which further cracking of the vapors does not take place to an appreciable extent.

A hydrocarbon distillate may be used as a chilling liquid it it is substantially free from heavy tarry materials and upon vaporizing chills the hot vapors to the desired temperatures. When a distillate to be cracked contains a quantity of light hydrocarbons it is advantageous to use such distillate as a cooling liquid, thereby removing the light vapors from the distillate before passing the distillate through the cracking coils. When using a hydrocarbon liquid or distillate, however, a larger quantity is required than when water is used. The amount used should be sufiicient to reduce the tem ierature of the vapors to a point at whici a substantial cracking of the distillate does not take place. The. distillate may be admitted to the inlet pipe 46 through a branch pipe 47, Fig. 1, leading from a distillate storage tank of other source of supply.

In the normal operation of the process there is no accumulation of liquid in the cooling drums, the water being completely vaporized, and any heavy oils cooled below their boiling points being carried out of the drums. From the cooling drums the steam and vapors pass through outlet pipes 48 to a collecting header 50 into which the vapors from all of the drums are delivered. From the header 50 the vapors pass through an ISO which the coils are suspended. To this end a supply of coal or other fuel is fed from a feeding hopper 54 to a traveling chain grate 56 extending through a combustion chamber 58 below the coils 40 in the furnace 42. The coal is uniformly distributed on the chain grate 56 by means of a regulating gate 60 or other suitable distributing means at the feed end of the grate. The grate 56 is positioned a sui'licient distance below the coils 40 to permit the complete combustion of the coal and of gases produced during combustion before the products of combustion come into contact with the coils.

Since the fresh fuel ordinarily has a longer flame than the partly cokedv and partly burned fuel, particularly'when bituminous or soft coal is used, the grate 56 is inclined upwardly toward its discharge end to give a longer path to the long flame portions of the fuel. The exact dimensions of the furnace will, of course, vary with different operating conditions and different types of fuel, but with ordinary coal a distance of from six to seven feet from the bed of coal to the bottom of the coils has been found satisfactory.

By thus completing combustion before the hot gases are brought into contact with the heating coils, local overheating of the coils due to irregularities in the combustion of the fuel is avoided and the hot products of combustion are brought to a uniform hightemperature before coming in contact with v the coils. The tendency towards the formation of deposits of soot on the heating coils is also lessened by this method of heating'. The hot products of combustion formed in the combustion chamber 58 pass upwardly through a heating chamber 62 in which the coils 40 are suspended and leave the heating chamber through a number of openings 6% connecting the chambers 62 with an exhaust fine 66.

The air for supporting combustion is supplied to the grate in such a manner as to maintain a substantially constant temperature throughout. the products of combustion flowing upwardly past the cracking coils.

, To this end the air for supporting combustion is forced by means of a fan 68, Figs. 1 and 2, to a wind box or air supply conduit 70, extending through the furnace at one side of, and a little below, the upper part of r the chain grate. From the wind box air is supplied through a number of openings 72, leading from the wind box to a number of air distributing troughs 7 4: extending across the furnace adjacent each other and opening upwardly under the upper part of the grate 56. The amount of air supplied to each of the distributing troughs 7 4: is controlled by means of a damper 7 6 partly closin the passageway 72. The dampers 7 6 are individually adjusted by means of an adj usting rod 7 8 extending through the oppoof air to each of the distributing troughs 7 f controlled to maintain a substantially uniform combustion throughout the length of the grate, and to produce'a substantially uniform temperature in the products of combustion passing upwardly from the combustion chambers 58. A supply of waste noncondensable gases resulting from the cracking, or other fluid fuel, may be supplied to the furnace through a burner 79 near the discharge end to maintain a constant temperature if the coal. tends to burn out before reaching the discharge end of the grate.

The temperature of the hot products of combustion entering the heating chamber 62 is measured by a number of pyrometers 80 of the thermo electric couple, or other suitable type, positioned in the lower part of the heating chamber 62. The pyrometers 80 are connected by means of connecting wires 82 to a switch board 84: and galvanometer 86 positioned in a control house 88, Fig. 1. Each of the pyrometers 80 may be separately connected with the galvanometer through switches 90 on the switch board 8st, Fig. 2, and the temperature at any portion of the furnace may be determined-in. this manner. The temperature of the hot products of combustion inthe upper part of the heating chamber 62 is measured by means of a number of pyrometers 92 spaced at intervals throughout the length of the furnace and connected by wires 94 to the switch board 84 and galvanometer 86. By means of this pyrometer arrangement an accurate measurement of the temperature throughout the furnace may be obtained at all times and the air supply to the fuel in the combustion chamber 58 may be adjusted in connection with these measurements to obtain the proper temperature condition in the furnace.

The maintenance of the proper temperature distribution in the furnace is controlled by means of a number of dampers 96 controlling the outlet openings 64 and adjustable by means of supporting rods 98 extend-- ing through the roof of the furnace. By means of damper controls, the volume of hot products of combustion passing through any part of the furnace and the distribution of the combustion gases may be controlled to regulate the temperatures throughout the heating chamber 62.

In. cracking a gas oil at a temperature somewhat below 1100 F. for instance, the temperature of lower part of the heating chamber 62 containing that portion of the cracking coils in which vaporization of the oil takes place is maintained at about 1500 F. and the temperature in the 11 )per part of the furnace surrounding the cratiking portion of the coils and adjacent the outlet openperatures which are, of course, merely given by way of example, are ordinarily obtained after the process has been operated for some time and conditions within the furnace have been stabilized.

An accurate measure of the temperature of the ingoing mixture of oil and steam is obtained by means of pyrometers 100 at the inlet end of the heating coils. The pyrometers 100 are connected to the switch board 84 and thegalvanomoter 86 by means of connecting wires 102. In a similar manner 'the temperature of the vapors passing from the coils 40 to the cooling drums is measured by means of pyrometers 104 connected to the switch board 84 by means of connecting wires 105. The determined temperature of the gases leaving the heating coil is main by means of pyrometers 106 and are regulated by controlling the. supply-of water or other liquid injected. A portion of the cracked products may be withdrawn from the pipes 44 thru test cocks 107 adjacent the header 46 and and an accurate control ofthe process thereby maintained.

The pressure in the pipe 51 is also deter mined by means of a pressure gauge 108 connected to the pipe through a connecting pipe 110. The pressure in the treating apparatus is. controlled from the control house by means of a valve spindle 112 connected to the valve 52 so that the pressure may be regulated in connection with the pressure gauge 108. The pressure at the outlet end of the coils may be adjusted to the type of oil belng treated and other conditions of operation, but is ordinarily somewhat less than pounds per square inch.

Owing to the high temperatures maintained in the furnace, the, heating coils 40 may gradually deteriorate after a long continued period of use, and may burn through or-burst under the pressure of the stream of steam and oil. 'VVhen this occurs, or when it is believed-that any coil has been weakened sufficiently to justify its removal and replacement, it is drawn upwardly out of the furnace by means of a traveling hoist.

To permit the easy removal and replace- I -1 nent of the coils, the coils are connected to the inlet and outlet pipes 38 and 44 respectively by means of flange unions 114 and 116 connecting the coils to the pipe 38 and 41- respectively. When the flange unions are disconnected the coil may be lifted directly out of the furnace by lifting the supporting means for the coil. This supporting device comprises an I-beam 117 supported a short distance above the furnace on transverse I-beam 118 and 120 at the front and rear of the furnace respectively. The coils are supported from the I-beam 117 by means of a number of hangers 121, which encircle the I-beam and extend downwardly around the individual heating coils. Another set of hangers 122 also extend dowmvardly from the I-bcam 117 and engage rods 12! extending the length of the furnace. Upon each rod there is strung a series of lire resistant. blocks 126. There is one rod 121. for each set of coils 40 and the series of: blocks 126 are of such a width that when all of the coils and suspending means arev in place the blocks form a continuous roof for the furnace. lVhen the flange unions 114 and 116 are disconnected. and a coil is to be removed from the furnace, the supporting I-beam 117 is lifted by means of hooks 128 supported from pulley 130 and with the -I-beam 117 a correspomling section of root blocks 126 and a coil 40 is lifted upwardly porting beam and corresponding roof section are then moved to one side of the furnace by means of a trolley 132, which supports the pulley 130 and which is itself supported bv a superstructure 134, which extends outwardly to one side of the furnace.

To prevent the rapid deterioration of the supporting hangers 120, a narrow arch 136 is constructed beneath each set of hangers and protects the bottom of the hanger from direct radiation from the fuel bed on the grate 56. The side of the furnace is also protected from rapid deterioration by direct contact with the glowing fuel by means of a water cooled clinker plate 138 adjacent the grate 56 and extending above it approximately or alittle greater than the depth of the fuel bed.

A small quantity of ash may sift downwardly from the grate 56 into the air distributing trough 74. This ash may be removed by means of a jet of steam admitted through a steam pipe 140 and directed adjacent the bottom of the arches to blow the ashes into a chute 142 extending downwardly into a drip channel 144. The condition of the troughs may be inspected by means of doors 146.

Owing. to the protective action of the steam preventing any particles of oil or decomposition products from contacting with and sticking to the wall of the heating coil, every portion of the oil passes at a uniform rate through the coil and receives the same heat treatment. This action, coupled with the uniform heating of the coil prevents a scorching of the oils undergoing treatment, and avoids the formation of scorched or charred compounds in the product obtained. The product accordingly has a pleasant odor and a very light color, being free from illsmelling compounds or any thing which would require that the product be subjected to the usual chemical treatment to remove impurities. As a result, a prodnot suitable for use as a motor fluid without further purification is obtained upon fractionally condensing and removing the heavier oils resulting from the reaction and subsequently condensing the light vapors. This product may of course be purified in the usual manner to produce a water white product if desired. A considerable saving of the light hydrocarbons is obtained when the product is used directly without a purification treatment and the lightest most volatile portions and other valuable constitu-v ents which are usually lost in the agitators are retained and add materially to the value of the product. Owing to the absence of scorching and to the uniform heat treatment, it has been found-that when sulphur containing oils are treated by this process, the sulphur in the oil is transformed to hydrogen sulphide or other sulphur compounds which do not contaminate the lighter hydrocarbons produced. The hydrogen sulphide or other sulphur compounds pass off with the waste or residue products and leave a pleasant smelling motor fuel which can be used directly without further purification. I

The motor fluid produced in the Present process may be distinguished from the ordinary types of natural or of cracked gasolenes by its pleasant odor, its slight yellow color, and the presence of substances ordinarily removed by treatment withsulphuric acid and alkali such as light hydrocarbons corresponding to casing head gasoline but produced as a result of cracking and accordingly containing an amount of unsaturated or olefine hydrocarbons. This motor fluid, therefore, has a greater density within the desired boiling point and a correspondingly greater fuel or power value.

The heavier fractions of the cracked products may be rerun through the cracking operation to produce additional quantities of light hydrocarbons or may be disposed of as a fuel oil or treated to produce other products.

While the above process has been specifically described as utilizing the steam for preventing scorching of the oil and diluting the hydrocarbon vapors, it is, of course, obvious that other agents having similar characteristics and properties could he substituted for steam for producing equivalent results in the final product.

Having described the invention, what is claimed as new is: I

1. A process of treating heavy hydrocarbon oils, which comprises mixing said oils with steam, passing the steam and oil under pressure, through a pipe extending back and forth through a furnace, burning a fuel in said furnace beneath said pipe throughout its length, )assing the products of con1bustion of said fuel into contact with said heat-- ing coils, supplying air in regulated streams throughout the length of said fuel bed to regulate said combustion to maintain a substantially constant temperature of said products of combustion throughout the length of said heating coils at temperatures sufficient to produce cracking of the oils, and bringing the vapors from said coils directly into con tact with a quantity of liquid'sufiicient to suddenly chill said products below a temperature at which further cracking of said oils will take place.

2. A process of treating hydrocarbon oils, which comprises passing a mixture of oils to be treated and steam through a long coil of pipe in a furnace, said mixture passing lengthwise in a number of successive passes at successive height-s, burning fuel below said coil, supplying air in a number of separately regulated quantities distributed throughout the horizontal length of the lower pass of said oil and steam mixture, said quantities being so regulated as to maintain a substantially uniform ten'iperature, above that required for cracking said oil, throughout each length of said coil, maintaining the passage of said oil and steam at a rate to obtain the desired cracking temperature in said coil, and suddenly chilling said treated oil by contact with a liquid immediately after leaving said coil.

3. A process of treating hydrocarbon oils which comprises passing a mixture of steam and oil to be treated through a coil of pipe extending lengthwise of a furnace, said steam and oil mixture entering the lower part and leaving the upper part of said coil, burning a solid fuel below said coil and throughout the length of said furnace, supplying air in separated regulated quantities distributed throughout the length of said 'fuel at a rate to maintain a substantially constant temperature suitable for cracking throughout the length of said coil, and rapidly chilling the product from said coil by direct contact with a liquid.

4. A process of treating hydrocarbon oils which comprises passing a mixture of steam and oil to be treated through a coil of pipe extending lengthwise of a furnace, said steam and oil mixture entering the lower part and leaving the upper part of said coil, maintaining said steam and oil above atmospheriopressure, burning a solid fuel below said coil and throughout the length of said furnace, supplying air in separated regulated quantities distributed throughout the length of said furnace at a rate to maintain a substantially constant temperature r suitable for cracking throughout the length of said coil, and rapidly chilling the product from said. coil by direct contact with a liquid immediately after leaving said coil.

5. A process of treating hydrocarbon oils which comprises passing a mixture of steam and oil to be treated through a coil of pipe extending lengthwise of said furnace, said steam and oil mixture entering the lower part and leaving the upper part of said coil, burning a solid fuel below said coil and throughout the length of said furnace, and supplying air in separated regulated quantities distributed throughout the length of said furnace at a rate to maintain a substantially constant temperature suitable for cracking throughout the length of said coil.

6. A process of treating hydrocarbon oils which comprises passing a mixture of steam and oil to be treated through a coil of pipe extending lengthwise of a furnace, said steam and oil mixture entering the lower part and leaving the upper part of said coil, burning a solid fuel below said coil and throughout the length of said furnace at a suflicient distance below the coil to permit a uniform distribution of heated gases throughout said furnace, and supplying air in separated regulated quantities distributed throughout the length of said furnace at a rate to maintain a substantially constant temperature suitable for cracking throughout the length of said coil.

In testimony whereof, I afiix my signature.

CHARLES JASON GREENSTREET. 

